Clavier-Übung (with or without the hyphen) is German for "keyboard practice". Two meanings of the word 'practice' in English are appropriate to this translation - first as in technical exercise, and second as in professional practice, as one practices law or medicine - the pieces both provide an opportunity to develop skill, as well as demonstrate the technical and stylistic conventions of keyboard composition and performance. In the late 17th and early 18th centuries this was a common title for keyboard music collections, initially popular after its adoption by Johann Kuhnau in 1689, although today it is usually associated with Johann Sebastian Bach's series of publications (see List of compositions by Johann Sebastian Bach printed during his lifetime). The above text from the Wikipedia article "Clavier-Übung" text is available under CC BY-SA 3.0.